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Question 1Anatomy and Physiology
How many bones are typically found in the adult human skeleton?
- 186
- 246
- 226
- 206 Correct answer.
Explanation
The adult skeleton typically contains 206 bones divided into the axial and appendicular divisions. Infants begin with more separate bones, many of which fuse during growth, which is why adult totals are lower than newborn totals.
Question 2Anatomy and Physiology
Which type of muscle tissue is striated and contracts involuntarily?
- Cardiac muscle Correct answer.
- Skeletal muscle
- Smooth muscle
- Tendon tissue
Explanation
Cardiac muscle shows striations because its fibers contain organized sarcomeres, but it contracts without conscious control through the heart's intrinsic conduction system. Skeletal muscle is striated yet voluntarily controlled, while smooth muscle is involuntary but lacks striations.
Question 3Anatomy and Physiology
Which anatomical plane divides the body into left and right portions?
- Oblique plane
- Frontal plane
- Transverse plane
- Sagittal plane Correct answer.
Explanation
The sagittal plane runs vertically from front to back, splitting the body into left and right sections. A midsagittal plane passes through the midline, while parasagittal planes lie parallel to it.
Question 4Anatomy and Physiology
Which of the following is classified as a hinge joint?
- Thumb carpometacarpal joint
- Elbow joint Correct answer.
- Hip joint
- Shoulder joint
Explanation
A hinge joint permits flexion and extension in a single plane, and the elbow is the classic example. The shoulder and hip are ball-and-socket joints with movement in multiple planes.
Question 5Anatomy and Physiology
Which blood component is primarily responsible for transporting oxygen?
- White blood cells
- Platelets
- Red blood cells Correct answer.
- Plasma proteins
Explanation
Erythrocytes are packed with hemoglobin, which binds oxygen in the pulmonary capillaries and releases it at the tissues. The other formed elements and plasma proteins serve different functions.
Question 6Anatomy and Physiology
What is the basic functional cell of the nervous system?
- Neuron Correct answer.
- Sarcomere
- Alveolus
- Nephron
Explanation
The neuron receives, integrates, and transmits electrochemical signals and is the functional unit of nervous tissue. The other options are functional units of muscle, kidney, and lung respectively.
Question 7Anatomy and Physiology
In which structures does gas exchange between air and blood occur?
- Pleura
- Trachea
- Alveoli Correct answer.
- Bronchi
Explanation
Alveoli are thin-walled sacs surrounded by capillary networks where oxygen and carbon dioxide diffuse across the respiratory membrane. The conducting airways simply move air toward these exchange surfaces.
Question 8Anatomy and Physiology
Which heart chamber has the thickest myocardial wall?
- Left ventricle Correct answer.
- Right atrium
- Right ventricle
- Left atrium
Explanation
The left ventricle ejects blood into the aorta against high systemic pressure, so its myocardium is the thickest of the four chambers. The right ventricle pumps into the low-pressure pulmonary circuit and therefore has a thinner wall.
Question 9Anatomy and Physiology
During a concentric contraction, what happens according to the sliding filament theory?
- The sarcomere lengthens as the Z lines move apart
- Myosin filaments shorten while actin remains still
- Actin slides past myosin, shortening the sarcomere Correct answer.
- Actin filaments dissolve to reduce sarcomere length
Explanation
Myosin heads attach to actin and pull the thin filaments toward the sarcomere center, so the sarcomere shortens while the filaments themselves keep their length. As a result the H zone and I band narrow and the Z lines move closer together.
Question 10Anatomy and Physiology
A marathon runner's postural muscles would be expected to contain a high proportion of which fiber type?
- An equal mix of all fiber types
- Type IIa fast oxidative fibers
- Type I slow oxidative fibers Correct answer.
- Type IIx fast glycolytic fibers
Explanation
Type I fibers have abundant mitochondria and capillaries and high fatigue resistance, making them dominant in endurance athletes and postural muscles. Fast-twitch fibers generate force quickly but fatigue sooner.
Question 11Anatomy and Physiology
Which protein covers the myosin binding sites on actin in a resting muscle?
- Titin
- Alpha-actinin
- Myosin light chain
- Tropomyosin Correct answer.
Explanation
In the resting state tropomyosin lies over the binding sites on actin, blocking cross-bridge formation. When calcium binds troponin, tropomyosin is displaced and the sites become available.
Question 12Anatomy and Physiology
Which neurotransmitter is released at the neuromuscular junction?
- Gamma-aminobutyric acid
- Acetylcholine Correct answer.
- Dopamine
- Norepinephrine
Explanation
Motor neurons release acetylcholine into the synaptic cleft, where it binds nicotinic receptors on the motor end plate and depolarizes the muscle fiber. Acetylcholinesterase then rapidly clears it to end the signal.
Question 13Anatomy and Physiology
Which cell is primarily responsible for forming new bone matrix?
- Chondrocyte
- Osteocyte
- Osteoblast Correct answer.
- Osteoclast
Explanation
Osteoblasts secrete osteoid and promote its mineralization, building new bone during growth and remodeling. Their counterparts resorb or maintain existing bone.
Question 14Anatomy and Physiology
How does the skeletal muscle pump support venous return during exercise?
- Compressing veins to push blood toward the heart Correct answer.
- Reducing heart rate during exercise
- Raising arterial pressure during rest
- Filtering plasma within the capillary beds
Explanation
Contracting limb muscles squeeze the deep veins, and one-way valves ensure the blood moves only toward the heart. This mechanism augments venous return and therefore end-diastolic volume during activity.
Question 15Anatomy and Physiology
A client has a resting heart rate of 70 beats per minute and a stroke volume of 70 mL per beat. What is the cardiac output?
- 2.8 L/min
- 6.3 L/min
- 3.5 L/min
- 4.9 L/min Correct answer.
Explanation
Cardiac output equals heart rate multiplied by stroke volume, so 70 beats per minute times 70 mL per beat equals 4900 mL per minute, or about 4.9 L/min. This relationship links heart rate and stroke volume to total blood flow.
Question 16Anatomy and Physiology
What does tidal volume measure?
- Volume moved in or out during one normal breath Correct answer.
- Volume of air left in the lungs after a maximal exhalation
- Maximum volume exhaled after a maximal inhalation
- Volume inhaled forcefully after a normal inhalation
Explanation
Tidal volume is the amount of air moved into or out of the lungs in a single quiet breath, roughly 500 mL at rest. It is distinct from the reserve volumes and from residual volume.
Question 17Anatomy and Physiology
Which hormone lowers blood glucose by promoting cellular glucose uptake?
- Insulin Correct answer.
- Epinephrine
- Cortisol
- Glucagon
Explanation
Insulin is released by pancreatic beta cells and lowers blood glucose by stimulating glucose uptake and glycogen storage. The other hormones listed act in the opposite direction.
Question 18Anatomy and Physiology
What does the size principle describe about motor unit recruitment?
- Motor units fire in random order regardless of the load
- The largest motor units are always recruited first to maximize force quickly
- Only slow-twitch units are used during maximal effort
- Units are recruited smallest to largest as force demand rises Correct answer.
Explanation
The size principle states that motor units are recruited in order of increasing size, beginning with small slow-twitch units and progressing to large fast-twitch units as force demand increases. This produces smooth gradation of force.
Question 19Anatomy and Physiology
Lactic acid produced during intense exercise is buffered primarily by which substance in the blood?
- Albumin circulating in plasma
- Phosphate salts stored in bone
- Bicarbonate dissolved in the blood Correct answer.
- Hemoglobin within red blood cells
Explanation
The bicarbonate system is the major extracellular buffer: bicarbonate combines with hydrogen ions to form carbonic acid, which is cleared as carbon dioxide at the lungs. This limits the fall in blood pH during intense exercise.
Question 20Anatomy and Physiology
What is the primary function of synovial fluid within a freely movable joint?
- Binds the bones together as a fibrous strap
- Produces red blood cells inside the joint cavity
- Lubricates the joint and nourishes articular cartilage Correct answer.
- Insulates the joint against temperature change
Explanation
Synovial fluid is a viscous filtrate of plasma that lubricates articulating surfaces, minimizes friction, and supplies nutrients to avascular articular cartilage. It also helps remove metabolic waste from the joint space.
Question 21Anatomy and Physiology
What is the role of the Golgi tendon organ during a maximal lift?
- Senses tendon tension and limits excess force Correct answer.
- Detects muscle length and rate of stretch
- Releases acetylcholine at the neuromuscular junction
- Signals joint position to the cerebellum
Explanation
Golgi tendon organs sit at the muscle-tendon junction and monitor tension, triggering reflexive inhibition when force becomes excessive. This protective reflex reduces the risk of tendon injury.
Question 22Anatomy and Physiology
Why does a muscle produce its greatest active tension at its optimal resting length?
- Optimal filament overlap maximizes cross-bridge formation Correct answer.
- The muscle is fully stretched so actin and myosin barely overlap
- Tendons store maximal elastic energy at that length
- The filaments overlap excessively when the muscle is shortened
Explanation
Active tension depends on how many cross-bridges can form, which is greatest when actin and myosin overlap optimally. Stretching the muscle reduces overlap, while shortening it causes filaments to collide, and both reduce force.
Question 23Anatomy and Physiology
What must occur for a myosin head to detach from actin after the power stroke?
- Calcium binding to troponin
- ATP binding to the myosin head Correct answer.
- Sodium influx into the muscle fiber
- Release of phosphate from the myosin head
Explanation
Binding of a new ATP molecule to the myosin head lowers its affinity for actin and causes detachment; hydrolysis of that ATP then re-cocks the head. Without ATP, cross-bridges remain locked, which is why rigor occurs after death.
Question 24Anatomy and Physiology
Why can a muscle typically produce more force during an eccentric action than a concentric one?
- The muscle shortens while producing tension
- Elastic elements and stretched cross-bridges add force Correct answer.
- Fewer motor units are recruited during a lengthening action
- ATP is not required during eccentric actions
Explanation
In an eccentric action the muscle lengthens while producing tension, so passive elastic components and forcibly detached cross-bridges contribute additional force. This allows higher loads than concentric work but also causes more muscle damage.
Question 25Anatomy and Physiology
According to the Frank-Starling mechanism, what happens when end-diastolic volume increases?
- Reduced venous return raises stroke volume
- Greater ventricular stretch increases stroke volume Correct answer.
- A higher heart rate directly increases stroke volume
- Increased afterload raises stroke volume
Explanation
Greater end-diastolic filling stretches the ventricular myocardium, which increases the force of contraction and therefore stroke volume. This intrinsic mechanism helps match cardiac output to venous return.
Question 26Anatomy and Physiology
Which type of blood vessel is the primary site of resistance to blood flow in the systemic circulation?
- Capillaries
- Arterioles Correct answer.
- Veins
- Large elastic arteries
Explanation
Peripheral resistance depends mainly on vessel radius, and the arterioles are small-diameter vessels with relatively thick smooth muscle that can constrict or dilate. Because they sit immediately before the capillary beds, changes in their radius regulate both blood pressure and the distribution of flow to tissues.
Question 27Anatomy and Physiology
During the standing (ascent) phase of a bodyweight squat, which muscle acts as the primary hip extensor?
- Tibialis anterior
- Iliopsoas
- Gluteus maximus Correct answer.
- Rectus femoris
Explanation
Rising from a squat requires extension at the hip and knee against gravity. The gluteus maximus is the largest and most powerful hip extensor and drives hip extension as the client stands, with the hamstrings assisting. Muscles that flex the hip or dorsiflex the ankle act in the opposite direction to the movement.
Question 28Anatomy and Physiology
A client performs a single all-out lift that lasts about five seconds. Which energy system supplies the majority of ATP for this effort?
- Phosphagen (ATP-PC) system Correct answer.
- Oxidative (aerobic) system
- Fat oxidation
- Fast glycolysis
Explanation
The phosphagen system uses stored ATP and creatine phosphate to regenerate ATP almost instantly without oxygen, but the supply is exhausted within roughly ten seconds. For very brief, maximal efforts such as a one-repetition lift, this system dominates before glycolysis and aerobic metabolism can make a meaningful contribution.
Question 29Anatomy and Physiology
At the very onset of aerobic exercise, heart rate climbs rapidly before venous return or blood chemistry has changed appreciably. Which mechanism best explains this early rise?
- Withdrawal of parasympathetic (vagal) tone to the sinoatrial node Correct answer.
- Increased circulating catecholamines released from the adrenal medulla
- A rise in core temperature caused by muscular heat production
- A decrease in afterload on the left ventricle
Explanation
Resting heart rate is held down by continuous vagal inhibition of the sinoatrial node. At exercise onset, central command from higher brain centers rapidly reduces this vagal outflow, allowing the intrinsic pacemaker rate to emerge and heart rate to rise within seconds. Hormonal and thermal influences develop more slowly and therefore explain later, not immediate, adjustments.
Question 30Anatomy and Physiology
During intense exercise, rising carbon dioxide and hydrogen ion levels in a working muscle shift its oxyhemoglobin dissociation curve to the right. What is the practical result of that shift?
- Hemoglobin transports a larger maximum number of oxygen molecules
- Hemoglobin binds oxygen more tightly within the lungs
- Hemoglobin releases more oxygen at a given tissue PO2 Correct answer.
- Oxygen dissolves more readily in the blood plasma
Explanation
A rightward shift means hemoglobin's affinity for oxygen is reduced, so at any given partial pressure of oxygen the hemoglobin is less saturated and gives up more oxygen to the tissue. The shift changes the ease of unloading, not the total capacity, which is fixed by the amount of hemoglobin present.
Question 31Kinesiology and Biomechanics
A standing biceps curl is performed primarily in which plane of motion?
- Oblique plane
- Sagittal plane Correct answer.
- Transverse plane
- Frontal plane
Explanation
Elbow flexion and extension rotate the forearm about a mediolateral axis, and that axis defines the sagittal plane. The sagittal plane divides the body into left and right segments, which is exactly the path the hand follows during a curl.
Question 32Kinesiology and Biomechanics
During the lowering phase of a back squat, the quadriceps are performing which type of muscle action?
- Concentric
- Isokinetic
- Eccentric Correct answer.
- Isometric
Explanation
An eccentric action occurs when a muscle develops tension while lengthening, which is what the quadriceps do as the knees and hips flex under load. This action controls the descent rather than producing the upward movement.
Question 33Kinesiology and Biomechanics
Which muscle group is the prime mover for knee extension?
- Gastrocnemius
- Quadriceps Correct answer.
- Hamstrings
- Hip adductors
Explanation
The quadriceps group crosses the anterior knee and pulls through the patellar tendon to extend the tibia. Its four heads make it the dominant extensor of the knee.
Question 34Kinesiology and Biomechanics
The humeroulnar joint of the elbow is best classified as which type of joint?
- Pivot
- Saddle
- Ball-and-socket
- Hinge Correct answer.
Explanation
A hinge joint permits motion in one plane, and the humeroulnar articulation allows only flexion and extension. Its bony configuration restricts rotation and side-to-side movement.
Question 35Kinesiology and Biomechanics
Type I muscle fibers are characterized by which trait?
- Rapid force production
- High resistance to fatigue Correct answer.
- Glycolytic dominance
- Large cross-sectional area
Explanation
Type I fibers are slow oxidative, with dense capillaries and high mitochondrial content, which makes them highly fatigue resistant. They suit sustained postural and endurance work rather than explosive output.
Question 36Kinesiology and Biomechanics
According to the sliding filament theory, which structure actually shortens during a concentric contraction?
- The tendon
- Myosin filaments
- Actin filaments
- The sarcomere Correct answer.
Explanation
Myosin heads pull actin filaments toward the center of the sarcomere, so the sarcomere shortens as the Z lines are drawn together. The filaments themselves keep a constant length while sliding past one another.
Question 37Kinesiology and Biomechanics
Raising the arm out to the side away from the body is a movement that occurs primarily in which plane?
- Transverse plane
- Oblique plane
- Sagittal plane
- Frontal plane Correct answer.
Explanation
Shoulder abduction rotates the arm about an anteroposterior axis, and that axis defines the frontal plane. The frontal plane divides the body into front and back halves, which is the direction the arm travels during abduction.
Question 38Kinesiology and Biomechanics
Which expression correctly calculates the torque (moment) produced by a muscle at a joint?
- Force × moment arm Correct answer.
- Impulse ÷ time interval
- Force × contraction velocity
- Mass × angular acceleration
Explanation
Joint torque equals the muscle force multiplied by the perpendicular distance from the force line of action to the joint axis. That perpendicular distance is the moment arm, so torque rises when either force or moment arm increases.
Question 39Kinesiology and Biomechanics
Compared with a concentric action at the same joint, a maximal eccentric action typically produces which outcome?
- Lower force output
- Greater force output Correct answer.
- Force output of zero
- Identical force output
Explanation
Eccentric actions can generate roughly 20 to 50 percent more force than concentric actions at the same joint because cross-bridges are loaded and elastic elements such as titin contribute. This is why lowering a load feels easier than lifting the same load.
Question 40Kinesiology and Biomechanics
Which muscles act as the primary movers for scapular retraction?
- Upper trapezius and levator scapulae
- Latissimus dorsi and teres major
- Rhomboids and middle trapezius Correct answer.
- Serratus anterior and pectoralis minor
Explanation
The rhomboids and middle trapezius pull the scapula toward the spine, which defines retraction. These muscles oppose the protractors during rowing and pulling movements.
Question 41Kinesiology and Biomechanics
According to the length-tension relationship, a muscle produces its greatest active tension when it is at which length?
- Maximally lengthened
- Stretched 20 percent beyond rest
- At its resting length Correct answer.
- Maximally shortened
Explanation
At resting length, actin and myosin overlap optimally, so the largest number of cross-bridges can form. Shortening or lengthening the muscle reduces that overlap and lowers active tension.
Question 42Kinesiology and Biomechanics
A closed kinetic chain exercise is best described as one in which which condition applies?
- The distal end moves freely through space
- Only a single joint is involved
- The proximal end is fixed in place
- The distal end is fixed in place Correct answer.
Explanation
In a closed chain, the distal segment is anchored against a fixed surface while the proximal segments move, as in a squat or push-up. An open chain has the distal segment free to travel, as in a leg extension.
Question 43Kinesiology and Biomechanics
Which proprioceptor detects changes in muscle length and contributes to the stretch reflex?
- Muscle spindle Correct answer.
- Pacinian corpuscle
- Ruffini ending
- Golgi tendon organ
Explanation
Muscle spindles lie parallel to the muscle fibers and fire when the muscle is stretched, driving the monosynaptic stretch reflex. This feedback helps regulate posture and protect against sudden lengthening.
Question 44Kinesiology and Biomechanics
Compared with a parallel-fibered muscle of equal volume, a highly pennate muscle generally has which characteristic?
- A larger range of motion
- A smaller cross-sectional area
- Higher force output Correct answer.
- Faster contraction speed
Explanation
Pennation packs more short fibers into the same volume, increasing physiological cross-sectional area and therefore force capacity. The trade-off is a shorter fiber length, which reduces both range of motion and contraction speed.
Question 45Kinesiology and Biomechanics
The rotary component of a muscle's force is greatest when its angle of pull is which value?
- 90 degrees Correct answer.
- 45 degrees
- 150 degrees
- 10 degrees
Explanation
The rotary component equals force times the sine of the angle of pull, and the sine reaches its maximum at 90 degrees. At that angle the entire force acts perpendicular to the bone, so no portion is wasted on compression or distraction.
Question 46Kinesiology and Biomechanics
A standing calf raise, where the ball of the foot serves as the fulcrum and body weight is resisted between the fulcrum and the pull of the Achilles tendon, is an example of which lever class?
- Second class Correct answer.
- Third class
- Fourth class
- First class
Explanation
In this arrangement the fulcrum sits at the ball of the foot, the resistance of body weight acts at the ankle between fulcrum and effort, and the effort comes from the calf through the calcaneus. A lever with the resistance in the middle is second class.
Question 47Kinesiology and Biomechanics
When the biceps brachii contracts strongly, reciprocal inhibition produces which effect on the triceps brachii?
- Increased spindle firing
- No change in activation
- Increased neural activation
- Reduced neural activation Correct answer.
Explanation
Reciprocal inhibition uses an inhibitory interneuron in the spinal cord to reduce drive to the antagonist while the agonist is active. This allows smoother movement and prevents opposing muscle groups from fighting each other.
Question 48Kinesiology and Biomechanics
A cable woodchop that rotates the trunk is performed primarily in which plane?
- Frontal plane
- Transverse plane Correct answer.
- Oblique plane
- Sagittal plane
Explanation
Trunk rotation occurs about a longitudinal axis, and that axis defines the transverse plane. The transverse plane divides the body into upper and lower halves, so rotation stays within it.
Question 49Kinesiology and Biomechanics
As the velocity of a concentric contraction increases, the force the muscle can produce does what?
- Remains constant
- Increases linearly
- Decreases Correct answer.
- Increases then plateaus
Explanation
The force-velocity relationship shows that concentric force falls as shortening speed rises, because faster cross-bridge cycling allows fewer bridges to stay attached at once. Peak force therefore occurs at zero velocity, which is an isometric action.
Question 50Kinesiology and Biomechanics
Active insufficiency of a two-joint muscle occurs in which situation?
- Loses neural input from its motor unit
- Is shortened over both joints at once Correct answer.
- Is inhibited by the antagonist
- Is lengthened over both joints at once
Explanation
When a two-joint muscle is shortened simultaneously at both joints it crosses, its fibers cannot shorten further and force production drops sharply. The hamstrings demonstrate this when the hip is extended and the knee flexed at the same time.